User:Apapadop

Hi, my name is Alex - I live in NW London and am a very early newbie in this (since 2009, getting a bit better in 2012...)

I use Linux and Windows machines and have a sysadmin background - currently focusing in usability and security of information systems. Own a Garmin GPSmap 60CSx unit that I used for a 6-month motorcycle trip from here to India - worked like a charm and the OSM maps were fantastic. I got the opportunity to contribute a little bit by uploading tracks from remote parts of India, but the 10,000 track points limit is killing me - given I don't like carrying a laptop around.

I'm preparing for a bicycle trip around Chile and trying to learn enough to make my time there as useful to OSM as possible, so if you have any tips on that please let me know!

Notes

My setup

System modifications

I've edited /etc/udev/rules.d/51-garmin.rules to include:

#Added by Alex for Garmin USB support on 05 April 2011
SYSFS{idVendor}=="091e", SYSFS{idProduct}=="0003", MODE="666"

This allows my regular (non-root) user to extract data from the GPS device. Without this line, only root can use gpsbabel to get data from the GPS. Regular users need to prefix any commands mentioned below by "sudo" and then supply their password.

Connecting the GPS to your computer

On connecting the GPS to the computer (laptop) with the USB cable and turning on the GPS, dmesg displays this line:

usb 3-1: new full speed USB device using uhci_hcd and address 2

Nothing else.

Transferring waypoints from the GPS to the computer

As a regular non-root user:

gpsbabel -w -i garmin -f usb: -o gpx -F GPS_waypoints.gpx

This creates the GPX file GPS_waypoints.gpx that contains all recorded waypoints (POIs).

This is a typical content of the GPS_waypoints.gpx file: (in this example it contains only three waypoints)

It contains some headers and then just a list of all the different trackpoints recorded - each one between <trkpt> </trkpt> tags.

Editing the track/trace you uploaded to OpenStreeetMap.org

Once you have successfully uploaded a GPX trace to OSM via http://www.openstreetmap.org/trace/create and got the "[OpenStreetMap] GPX Import Success" email, you can click on the "edit" link from your trace's page (e.g. http://www.openstreetmap.org/edit?gpx=1078390 - but change the final number to the unique number of your uploaded trace) and then Potlatch 2 will start, showing you an editable version of the map, including aerial imagery, with your trace pre-loaded.

It is sometimes difficult to distinguish your trace from all the other OSM information already on the map. This is what the screen looks like for a second or two:

It is easy to see your trace (in light blue) on the aerial images.

The problem is that then all the other map information is loaded:

This makes it harder to see your trace - which you can still barely distinguish with the same light-blue/cyan color.

Zooming in makes the trace easier to edit.

Transferring routes from the computer to the GPS

To send the route "home_to_work.gpx" to the GPS:

gpsbabel -r -i gpx -f home_to_work.gpx -o garmin -F usb:

Adding waypoints to OSM

This method (using Potlatch for the final editing) has a number of limitations (labour intensive, not flexible enough, error prone etc), but it's simple. Plus, I haven't had the time/courage to figure out how JOSM works yet. Plus, I want to do all this while travelling so keeping the list of tools I need as slim as possible is a must. Potlatch will always be available on the OSM website, and will work from any Internet Cafe.

I want to add 50 new waypoints to OSM!

Great, me too! I went travelling for a few months and when I returned I had many Points of Interest that I wanted to add to the map, but didn't know how. I've found a (probably completely stupid) way of doing it:

Now cut'n'paste waypoints to other, smaller files. My waypoints were of all sorts (restaurants, water sources, toilets, police checkpoints, camp sites, petrol stations, embassies etc) from Turkey, Iran, Pakistan and India. I found it easier to break up the large GPX file into smaller files

Take one of the smaller files and following the instructions in the Upload Waypoints page, upload the GPX to OpenStreetMap.org.

Activate the "show coordinates" option in Potlatch2

Use your keyboard's arrow keys to navigate to the next waypoint and tag it appropriately.

Save when you're done.

I have a GPX file with no timestamps

Yes, it is rejected by OSM.

There is a reasonable way around it.
(but also see next section for an automatic workaround)

Upload track_timestamped.gpx to OpenStreetMap - it should now be accepted.

HOWTO create GPX files with timestamps

On my Garmin GPSmap 60CSx it seems that the default setup is to save GPX files to the internal memory (not the removable SD card), which is very limited, hence the device tries to save space by discarding the timestamps and each track log is restricted to 500 points.

But, if setup to save recorded tracks onto the SD card (also known as "Data card"), it appears that timestamps are preserved and track logs can be as long as 10.000 points.

These GPX files (that the unit directly saves on the data card - you have little control of what and how is saved or named) are accepted by Openstreetmap with no hiccups.

To setup my device to do this I had to go to the "Track Log" page and then:

HOWTO select entire track in Potlatch 2

Say you have just uploaded a GPX with a long track - hundreds of trackpoints. You obviously have better things to do than re-drawing this manually, so you just want to select the entire track and convert it to a way. To do this:

On a Windows-based system you can ALT-click anywhere on the track.

On a Linux-based system you can CTRL-SHFT-click anywhere on the track.

Voila, now all trackpoints have been selected.

What's a standard GPX file header?

If you have created a GPX file that contains only <wpt> stanzas like this:

HOWTO merge (combine) ways in Potlatch 2

This is useful when you want to combine (connect) two segments of the same road, to form ONE road.

Click to select the first way

Hold down CTRL-SHFT and click on second way

Click on the "Merge ways" button of the toolbar on the bottom right.

Note: This will not work (the button will be unavailable) if the two ways have overlapping points.

HOWTO resolve alignment conflicts between OSM ways and aerial imagery

Assume you're editing with Potlatch 2 and you come to something like this:

The problem here is that aerial imagery is not aligned with the ways already mapped. So you need to decide which one is right here: The aerial image? Or the mapped ways?

Click on the indicated "GPS Data" button. This will bring up any GPS trace data existing for that area, as thin cyan (light blue) lines. You can barely see it in this example on the left side of the triangular road intersection. The important bit here is not perfect alignment - but this thin blue line indicates that someone moved through that space with a GPS, so the road is probably there.

Which means that in this example, the ways mapped in OSM are correct, and the aerial imagery background has to be adjusted before you do any further mapping. You can do this by holding down SPACE on your keyboard and dragging the aerial image with your mouse, until it aligns with the OSM ways.